The present invention relates to proteins that are involved in inflammation and immunomodulation, survival, or activation or in lymphoproliferative disorders or other cancers. The invention further relates to proteins related to the tumor necrosis factor (TNF)/nerve growth factor (NGF) superfamily and related nucleic acids, expression vectors, host cells, and binding assays. The specification also describes compositions and methods for the treatment of immune-related and inflammatory, autoimmune and other immune-related diseases or disorders, such as rheumatoid arthritis (RA), Crohn""s disease (CD), lupus, and graft versus host disease (GvHD) as well as for treatment of lymphoproliferative diseases and other cancers.
After years of study in necrosis of tumors, tumor necrosis factors (TNFs) xcex1 and xcex2 were finally cloned in 1984. The ensuing years witnessed the emergence of a superfamily of TNF cytokines, including fas ligand (FasL), CD27 ligand (CD27L), CD30 ligand (CD30L), CD40 ligand (CD40L), TNF-related apoptosis-inducing ligand (TRAIL, also designated AGP-1), osteoprotegerin binding protein (OPG-BP or OPG ligand), 4-1BB ligand, LIGHT, APRIL, and TALL-1. Smith et al. (1994), Cell, 76: 959-962; Lacey et al. (1998), Cell, 93: 165-176; Chichepotiche et al. (1997), J. Biol. Chem., 272: 32401-32410; Mauri et al. (1998), Immunity, 8: 21-30; Hahne et al. (1998), J. Exp. Med., 188: 1185-90; Shu et al. (1999), J. Leukocyte Biology, 65: 680-3. This family is unified by its structure, particularly at the C-terminus. In addition, most members known to date are expressed in immune compartments, although some members are also expressed in other tissues or organs, as well. Smith et al. (1994), Cell 76: 959-62. All ligand members, with the exception of LT-xcex1, are type II transmembrane proteins, characterized by a conserved 150 amino acid region within C-terminal extracellular domain. Though restricted to only 20-25% identity, the conserved 150 amino acid domain folds into a characteristic xcex2-pleated sheet sandwich and trimerizes. This conserved region can be proteolyticaly released, thus generating a soluble functional form. Banner et al. (1993), Cell, 73: 431-445.
Many members within this ligand family are expressed in lymphoid enriched tissues and play important roles in the immune system development and modulation. Smith et al. (1994). For example, TNFxcex1 is mainly synthesized by macrophages and is an important mediator for inflammatory responses and immune defenses. Tracey and Cerami (1994), Annu. Rev. Med., 45: 491-503. Fas-L, predominantly expressed in activated T cell, modulates TCR-mediated apoptosis of thymocyts. Nagata, S. and Suda, T. (1995) Immunology Today, 16:39-43; Castrim et al. (1996), Immunity, 5:617-27. CD40L, also expressed by activated T cells, provides an essential signal for B cell survival, proliferation and immunoglobulin isotype switching. Noelle (1996), Immunity, 4:415-9.
The cognate receptors for most of the TNF ligand family members have been identified. These receptors share characteristic multiple cysteine-rich repeats within their extracellular domains, and do not possess catalytic motifs within cytoplasmic regions. Smith et al. (1994). The receptors signal through direct interactions with death domain proteins (e.g. TRADD, FADD, and RIP) or with the TRAF proteins (e.g. TRAF2, TRAF3, TRAF5, and TRAF6), triggering divergent and overlapping signaling pathways, e.g. apoptosis, NF-xcexaB activation, or JNK activation. Wallach et al. (1999), Annual Review of Immunology 17: 331-67. These signaling events lead to cell death, proliferation, activation or differentiation. The expression profile of each receptor member varies. For example, TNFR1 is expressed on a broad spectrum of tissues and cells, whereas the cell surface receptor of OPGL is mainly restricted to the osteoclasts. Hsu et al. (1999) Proc. Natl. Acad. Sci. USA, 96:3540-5. Such proteins are believed to play a role in inflammatory and immune processes, suggesting their usefulness in treating autoimmune and inflammatory disorders.
A number of research groups have recently identified TNF family ligands with the same or substantially similar sequence, but they have not identified the associated receptor. The ligand has been variously named neutrokine-xcex1 (WO 98/18921, published May 7, 1998), 63954 (WO 98/27114, published Jun. 25, 1998), TL5 (EP 869 180, published Oct. 7, 1998), NTN-2 (WO 98/55620 and WO 98/55621, published Dec. 10, 1998), TNRL1-alpha (WO 9911791, published Mar. 11, 1999), kay ligand (WO99/12964, published Mar. 18, 1999), and AGP-3 (U.S. Prov. App. No. 60/119,906, filed Feb. 12, 1999 and No. 60/166,271, filed Nov. 18, 1999, respectively). Each of these references is hereby incorporated by reference. Hereinafter, this protein sequence is referred to as xe2x80x9cAGP-3.xe2x80x9d
A recent paper has identified two previously known proteins as receptors for AGP-3. Gross et al. (2000), Nature 404: 995-9. The first receptor was previously identified as a lymphocyte surface receptor named Transmembrane Activator and CAML Interactor (TACI). See WO 98/39361, published Sep. 11, 1998, and von Bulow and Bram (1997), Science, 278:138-140, each of which is hereby incorporated by reference in its entirety. According to these references, TACI binds an intracellular cyclophilin ligand designated CAML, which modulates the calcium signaling pathway in lymphocytes.
The second receptor identified for AGP-3 is the so-called B cell maturation protein (BCMA). The human BCMA gene was discovered by molecular analysis of a t(4;16) translocation, which characteristic of a human T cell lymphoma. Laabi et al. (1993), EMBO J. 11: 3897-3904. BCMA mRNA was reported to be found mainly in lymphoid tissues. Human BCMA cDNA encodes a 184 amino acids protein (185 residues for the mouse), and the literature reports no obvious similarity with any known protein or motif, and its function remained unknown. The protein was reported to reside in the Golgi apparatus (Gras et al. (1995), Intl. Immunol. 7: 1093-1106). Recent speculation suggested that BCMA may be a distant member of the TNFR super family. Madry et al. (1998), Intl. Immunol. 10: 1693-1702.
A ligand called APRIL or G70 is a TNF family ligand that remains without a receptor reported in the literature. According to the literature, APRIL is associated with prostate cancer, breast cancer, Alzheimer""s disease, immune disorders, inflammatory disorders, and gestational abnormalities. See WO 99/00518 (Jun. 26, 1997); WO 99/11791 (Sep. 5, 1997); WO 99/12965 (Sep. 12, 1997); EP 911 633 (Oct. 8, 1997); EP 919 620 (Nov. 26, 1997); WO 99/28462 (Dec. 3, 1997); WO 99/33980 (Dec. 30, 1997); WO 99/35170 (Jan. 5, 1998); and Hahne et al. (1998), J. Exp. Med. 188: 1185-90. (Each of the foregoing references is hereby incorporated by reference in its entirety.) A recent paper described APRIL isoforms and suggested that APRIL causes cell death. Kelly et al. (2000), Cancer Res. 60: 1021-7. The art would benefit from identification of a receptor for APRIL and a clarification of its activity.
It has now been found that sG70 (APRIL) binds to cell-surface receptors on T and B lymphoma cells resulting in stimulation of proliferation of primary human and mouse B and T cells both in vitro and in vivo. It has now been found that BCMA and TACI are cell-surface receptors for APRIL. It has also been found that APRIL competes with AGP3xe2x80x2s binding to TACI and BCMA. Furthermore it is shown here that sBCMA inhibits APRIL and AGP3 binding to its receptors. sBCMA ameliorates T cell dependent and T cell independent humoral immune responses in vivo. In addition it has now been found that sTACI inhibits APRIL and AGP3 binding to its receptors and ameliorates T cell dependent and T cell independent humoral immune responses in vivo. In addition it has now been found that sBCMA reduces lymphoma and colon carcinoma cell tumor growth in vivo. It has also now been found that sBCMA increases survival and reduces incidence of proteinurea, and development of anti-dsDNA antibodies in an animal model of lupus. It has also been found that BCMA exhibits similarity with TACI within a single cysteine rich domain located N-terminal to a potential transmembrane domain. It has also been found that APRIL stimulates B cell growth and immunoglobulin production in vitro and in vivo. Furthermore, treatment with a blocking anti-APRIL antibody ameliorates generation of antigen specific immunoglobulin, suggesting that endogenous APRIL is required for humoral immunity in vivo. This invention concerns novel methods of use and compositions of matter that exploit these discoveries. The discoveries provides a strategy for development of therapeutics for treatment of autoimmune diseases, and cancer, for prevention of transplant rejection.
These discoveries show that activity, disease states, and disease parameters associated with APRIL and AGP-3 may be affected by modulation of BCMA. Likewise, disease states and disease parameters associated with TACI can be affected by modulation of APRIL. Further, such disease states and disease parameters can be affected by modulation of any of TACI, BCMA, APRIL and AGP-3 together. This discovery further suggests molecules and methods of treatment by which more than one of TACI, BCMA, APRIL, and AGP-3 may be modulated by a single molecule.